The mite Varroa destructor is an important honey bee parasite that causes substantial losses of honey bee colonies worldwide. Evolutionary theory suggests that the high densities at which honey bees are managed in large-scale beekeeping settings will likely select for mites with greater growth and virulence, thereby potentially explaining the major damage done by these mites. We tested this hypothesis by collecting mites from feral bee colonies, “lightly” managed colonies (those from small-scale sedentary operations), and “heavily” managed colonies (those from large-scale operations that move thousands of colonies across the US on a yearly basis). We established 8 apiaries, each consisting of 11 colonies from a standardized lightly managed bee background that were cleared of mites, and artificially infested each apiary with controlled numbers of mites from feral, lightly managed, or heavily managed bees or left uninoculated as negative control. We monitored the colonies for more than 2 years for mite levels, colony strength (adult bee population, brood coverage, and honey storage), and survival. As predicted by evolutionary theory, we found that colonies inoculated with mites from managed backgrounds had increased V. destructor mite levels relative to those with mites from feral colonies or negative controls. However, we did not see a difference between heavily and lightly managed colonies, and these higher mite burdens did not translate into greater virulence, as measured by reductions in colony strength and survival. Our results suggest that human management of honey bee colonies may favor the increased population growth rate of V. destructor, but that a range of potential confounders (including viral infections and genotype-by-genotype interactions) likely contribute to the relationship between mite reproduction and virulence.

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评估来自不同蜜蜂管理制度的瓦螨的毒力

螨瓦螨破坏者是一种重要的蜜蜂寄生虫，会导致全世界蜜蜂群的大量损失。进化理论表明，在大规模养蜂环境中管理蜜蜂的高密度可能会选择生长和毒力更大的螨虫，从而可能解释这些螨虫造成的主要损害。我们通过从野蜂群、“轻度”管理的蜂群（来自小规模久坐活动的蜂群）和“重度”管理的蜂群（来自在美国各地移动数千个蜂群的大规模行动中的蜂群）收集螨虫来检验这一假设。每年一次）。我们建立了 8 个养蜂场，每个养蜂场由 11 个来自标准化的轻管理蜜蜂背景的蜂群组成，这些蜂群已经清除了螨虫，并用受控数量的来自野生、轻度管理或重度管理的蜜蜂的螨虫人工感染每个养蜂场，或者不接种作为阴性对照。我们对蜂群的螨虫水平、蜂群强度（成年蜜蜂种群、育雏覆盖率和蜂蜜储存量）和存活率进行了 2 年多的监测。正如进化理论所预测的那样，我们发现接种来自管理背景的螨虫的菌落与来自野生菌落或阴性对照的螨虫相比，V. destructor 螨虫水平增加。然而，我们没有看到重度管理和轻度管理的菌落之间的差异，并且这些更高的螨虫负担并没有转化为更大的毒力，这是通过菌落强度和存活率的降低来衡量的。